Help me understand which CFL bulbs give off the same amount of light as a conventional 100 watt bulb.

I see many references to 60W bulb similarity when I look at these CFLs; I'm not interested in 60W bulb equivalents. I want, if they exist, CFL bulbs that give off the same amount of light as a 100W bulb.

How do I figure this out? Is a 100W CFL bulb different than a 100W incandescent bulb?

Watts measure energy, not light. Watts were a measure of incandescent light bulbs, because the amount of wattage used = light output. Obviously, that's not the case with CFLs, since they use much less energy and produce the same amount of light.

CFL's are listed with Watt equivalents for ease of the consumer. If you go to the store, you'll find a whole range of CFL "wattages".

light sources are measured in lumens, usually. you can find out how many lumens your normal incandescent bulbs put out by reading the box; this same info will be printed out on the packaging for the CFLs as well. this is a pretty basic overview of it.

CFLs work more efficiently than incandescent bulbs and therefore use less wattage to deliver an equivalent amount of lumens. best to compare lumens rather than wattages, though the model names of CFLs tend to include the wattage of incandescent bulb that the CFL is meant to replace.posted by mrg at 4:56 PM on May 29, 2009 [2 favorites]

A 100-watt incandescent bulb produces 1700-1800 lumens (a measure of total light output), so just look for CFLs with a similar lumen output. Being more efficient than incandescent lights, these will consume much less than 100 watts.

You will also want to pay attention to the colour of the CFLs that you buy. It will usually be printed on the packaging as a colour temperature, a number with a K (for kelvin) after it. If you want it to look like an incandescent light, then somewhere around 2700-3000K should be about right. This is quite "red" or "warm" in colour. Higher numbers are more "blue" or "cold" looking and many people don't like that.posted by FishBike at 4:56 PM on May 29, 2009 [3 favorites]

CFL's put out about 4 times the light at the same wattage incandescent.

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